Parenteral solution delivery is usually accomplished using fluid pressure provided by hanging the solution source above the patient. This practice has continued despite the development of newer fluid reservoir systems such as plastic bags and the development of precision pumping systems. Obstructions of the delivery system within the body of the patient are common due to clotting, body movement, infiltration (extravasation), catheter position (proximity of vessel wall to catheter end), vein collapse and the like. This increases fluid pressure in the system between the pump and the patient until the pressure frees the blockage or the motor stops, unless the system has a safety system disengaging the pump motor from the pump or a safety valve releasing the pressure.
Sudden blow-out of the blockage poses a serious danger to the patient. To prevent this, it is necessary to sense any significant increase in fluid pressure between the pump and patient and to immediately stop the pumping action. The devices heretofore available do not have the required sensitivity, and the risk of patient injury from parenteral pump delivery systems continues.